1. Field of the Invention
The present invention relates to grease recovery devices for separating grease, fats and oils from wastewater and, more specifically, to an automatic grease interceptor.
2. Prior Art
Grease interceptors are used in plumbing wastewater systems to permit free flow of drainage from sinks and similar equipment and to prevent grease accumulations from clogging connecting piping, sewer lines and wastewater treatment plants. The process of grease interception is simply the separating and retaining of globules of grease, fats and oils from wastewater as it passes through a grease interceptor.
Small molecules of grease unite together in wastewater, cling to and accumulate on the inside of pipelines clogging drainage lines from sinks, dishwashers and other sources of grease-laden wastewater. In food service and other commercial and industrial applications, wastewater is generated with high grease or animal fat content. As this wastewater is discharged through the wastewater disposal system, the grease accumulates on the interior walls of the wastewater pipe. As the grease coating grows, it obstructs the flow of wastewater in the sewage pipe.
To permit adequate flow, the obstruction must be removed by unearthing and working on the pipe. This is a costly and time-consuming procedure. Grease interceptors are utilized to intercept and remove the grease prior to entrance in the disposal system.
The most common method of grease extraction is the use of a vessel placed in line with a wastewater disposal pipe. This device usually uses gravity to separate grease from water. The operating principle behind a gravity separator is that grease has a lower specific gravity than water and therefore floats to the surface inside the intercepting vessel. In standard grease interceptors, once the grease interceptor has reached full capacity, the wastewater inlet must be closed, the lever removed and the grease ladled out manually. The lever can then be replaced and the process repeated. This manual removal procedure is somewhat time-consuming and inefficient.
Another method of grease extraction involves the use of enzymes to digest the grease prior to entry into the discharge system. The major difficulty with the enzyme solution is the sensitivity of the enzyme to the environment. The enzyme is only able to survive in a very narrow temperature and humidity band which are difficult to maintain within a dynamic situation such as a wastewater pipe. Furthermore, the recovered grease has a salvage value which is valuable to the user. The use of enzymes to digest the grease can minimize the potential recovery of salvaged grease.
Another known method of grease interception is to place a device inside the recovery vessel to automatically remove the grease. Generally, these systems will run the automatic grease remover for a fixed duration each day. This operation presents several problems. If the automatic grease remover is not run long enough each day, not all of the grease generated in that period will be removed, causing a continual buildup of grease and the need for an eventual manual cleaning. Alternatively, if the automatic grease remover is run for too long a period, it will begin to remove water from the recovery vessel, ruining the commercial value of the salvaged grease.
The object of the present invention is to provide an automatic, electronic grease recovery device which minimizes the need for user intervention. Another object of the present invention is to provide a device that maintains the purity of the salvaged grease and eliminates grease buildup within the intercepting device. A further object of the present invention is to overcome all of the aforementioned drawbacks of the prior art.